Electrochemical activation combined with advanced oxidation on NiCo2O4 nanoarray electrode for decomposition of Rhodamine B

Peroxymonosulfate (PMS) is a strong oxidizing agent that can generate reactive oxygen species (ROSs) to decompose organic pollutants . It can be activated by either chemical catalysis or electrochemical processes, both of which are limited by low catalytic efficiency. In this study, electrochemical oxidation and advanced oxidation of PMS on a NiCo 2 O 4 nanoarray cathode were integrated to decompose Rhodamine B (RhB). The combined method exhibited faster decolourisation rates and increased reaction efficiencies compared to systems using either electrochemistry or PMS alone. The effects of pH, PMS dosage, initial RhB concentration, and current density were investigated. The activation of PMS (2 g·L −1 ) under a current density of 10 mA·cm -2 at neutral pH showed a high decolourisation efficiency of 99.7 % for the RhB solution (100 mg L −1 ) in 60 min. The corresponding total organic carbon (TOC) removal efficiency was 28.9 %. The electrode could be reused for at least four cycles while maintaining its high activity. Furthermore, scavenging experiments were conducted with various radical scavengers to identify the major ROSs. Our mechanistic study suggested that O 2 - and 1 O 2 play key roles in the degradation process. A synergistic effect was promoted by combining electrochemical and chemical processes for PMS activation . The results presented herein provide fundamental insight into advanced oxidation processes with PMS.